You are in Ireland. The message points out that cars can't be sent to ireland.
In fact, cars are not "sent" anywhere. They are normally collected in person, and not paid for until you have seen and inspected the vehicle, checked the paperwork and had an HPI check.
I don't think that eBay prohibits bids from sellers in Ireland (North or South). It's more likely that the sellers have chosen to block bids from buyers located outside the UK. If you were planning to travel to the UK you could try messaging the sellers to ask whether they're willing to put you on an exception list, to allow you to bid.